The present invention relates to a connector requiring impedance matching for electric characteristics, e.g., an increase in speed of LVDS, TMDS, PCI express transmission, etc., and more particularly relates to a connector having a joining portion joined to a substrate by soldering, etc., and a fitting portion coming in contact with a partner side connector, FPC or PCB.
A connector is shown in Japanese Patent Application Publication (JP-A) No. 2001-511300 (corresp. to WO98/35408), hereinafter called Reference 1, as the connector for connecting substrates to each other. The connector shown in Reference 1 is a connector for connecting two substrates so as to be perpendicular to each other and has a large-sized structure.
A socket connector and a plug connector are arranged in each of the mutual substrates to connect the substrates to each other. The substrates are connected by fitting these connectors to each other.
However, it is required that the connector for connecting printed boards to each other satisfies characteristics at high frequency in a field in which an electric signal becomes a high frequency wave. Further, the request of high density mounting is more and more increased. Therefore, a reduction in the pitch of a contact is also required.
In the conventional high speed signal transmission connector, the pitch between terminals as the distance between signal contacts as a pair must be increased to a certain extent for the purpose of electric characteristics such as matching of impedance at a differential transmission time. Therefore, there is a defect in that the connector is large-sized.
Further, in the connector of this kind, there is also an example in which the distance between the signal contacts as a pair is increased by arranging a dummy terminal for positively flowing no electric current between the signal contacts as a pair, and impedance is matched. However, a useless terminal or contact is correspondingly inserted so that there is a defect in that the connector becomes expensive.
On the other hand, there is a case opposed to the reduction in pitch as impedance characteristics among the electric characteristics. There is a defect in that the pitch of the connector is increased and the size of the connector itself is increased when the electric characteristics are preferentially set.
Further, there is a defect in that no electric characteristics are matched when the pitch is reversely preferentially reduced.